HIGH-EFFICIENCY SINGLE-INPUTMULTIPLE-OUTPUT DC-DC CONVERT

Submitted by K. PRAVEEN KUMARReg.No.12371D0708

ABSTRACT The aim of this study is to develop a high-

efficiency single-input multiple-output (SIMO) dc–dc converter.

The proposed converter can boost the voltage of a low-voltage input power source to controllable high-voltage dc bus and middle-voltage output terminals.

In this study, a coupled-inductor baseddc–dc converter scheme utilizes only one power switch with the properties of voltage clamping and soft switching, and the corresponding device specifications are adequately designed.

INTRODUCTION Dc-Dc converter topologies Resonant converters Power electronics switches Proposed system working principle Simulation results Future scope

DC-DC CONVERTER TOPOLOGIES The power electronic converters are

classified into six types:1. Diode rectifiers2. AC-DC converter (Phase controlled

Rectifiers)3. DC-DC converters (DC choppers)4. DC-AC converters (Inverter)5. AC-AC converters

i. AC voltage controllersii. Cyclo converters

6. Static switches

RESONANT CONVERTERS

It is known as DC to DC Converter or Dc to Ac PWM inverter.

Resonant inverters are electrical inverters based on resonant current oscillation.

The current through the switching devices fall to zero due to the natural characteristics of the circuit.

If the switching element is a thyristor, it is said to be self-commutated.

Resonant inverters are electrical inverter based on resonant current oscillation.

CLASSIFICATION: Series Resonant inverter Parallel Resonant inverter Class E Resonant Converter Class E Resonant Rectifier Zero Voltage Switching(ZVS) Resonant

Converter Zero Current Switching(ZCS) Resonant

Converter Two Quadrant ZVS Resonant Converter Resonant dc-link inverter

POWER ELECTRONICS SWITCHES

Semiconductors:

It act as switching device in the power electronic converters.

It is defined as the material whose conductivity depends on the energy (light, heat, etc.,) falling on it.

Semiconductor switches are

Diodes, SCR, MOSFET, IGBT, BJT, TRIAC etc.

IGBT ( THE INSULATED-GATE BIPOLAR TRANSISTOR )

IGBT is a three-terminal power semiconductor device noted for high efficiency and fast switching.

The IGBT is used in medium- to high-power applications such as switched-mode power supply traction motor control and induction heating.

PROPOSED SYSTEM WORKING PRINCIPLE

INTRODUCTION

IN ORDER to protect the natural environment on the earth, the development of clean energy without pollution has the major representative role in the last decade.

By dealing with the issue of global warning, clean energies, such as fuel cell (FC), photovoltaic, and wind energy, etc., have been rapidly promoted.

Due to the electric characteristics of clean energy, the generated power is critically affected by the climate or has slow transient responses, and the output voltage is easily influenced by load variations

Fig. 1. System configuration of high-efficiency single-input multiple-output (SIMO) converter.

Fig. 2. Equivalent circuit.

.1) Mode 1 (t0 –t1 ) [Fig. (a)]: In this mode, the main switchS1 was turned ON for a span, and the diode D4 turned OFF.

Because the polarity of the windings of the coupled inductor Tr is positive, the diode D3 turns ON. The secondary current iLs reverses and charges to the middlevoltage capacitor C2 .

When the auxiliary inductor Laux releases its stored energy completely, and the diode D2 turns OFF, this mode ends.

2) Mode 2 (t1 –t2 ) [Fig. (b)]: At time t = t1 , the main switch S1 is persistently turned ON.

Because the primary inductor LP is charged by the input power source, the magnetizing current iLmp increases gradually in an approximately linear way. At the same time, the secondary voltage vLs charges the middle-voltage capacitorC2 through the diode D3

stored energy completely, and the diode D2 turns OFF at the end of mode 1, it results in the reduction of diLkp /dt at mode 2.

3) Mode 3 (t2 –t3 ) [Fig. (c)]: At time t = t2 , the main switch S1 is turned OFF.

When the leakage energy still released from the secondary side of the coupled inductor, the diode D3 persistently conducts and releases the leakage energy to the middle-voltage capacitor C2 .

When the voltage across the main switch vS 1 is higher than the voltage across the clamped capacitor VC 1 , the diode D1 conducts to transmit the energy of the primary-side leakage inductor Lkp into the clamped capacitor C1 .

At the same time, partial energy of the primary-side leakage inductor Lkp is transmitted to the auxiliary inductor Laux, and the diode D2 conducts. Thus, the current iL aux passes through the diode D2 to supply the power for the output load in the auxiliary circuit.

When the secondary side of the coupled inductor releases its leakage energy completely, and the diode D3 turns OFF, this mode ends.

4) Mode 4 (t3 –t4 ) [Fig. (d)]: At time t = t3 , the main switch S1 is persistently turned OFF. When the leakage energy has released from the primary side of the coupled inductor,

the secondary current iLS is induced in reverse from the energy of the magnetizing inductor Lmp through the ideal transformer, and flows through the diode D4 to the HVSC. At the same time, partial energy of the primaryside leakage inductor Lkp is still persistently transmitted

5) Mode 5 (t4 –t5 ) [Fig. (e)]: At time t = t4 , the main switch S1 is persistently

turned OFF, and the clamped diode D1 turns OFF because the primary leakage current iLkp equals to the auxiliary inductor current iL aux.

In this mode, the input power source, the primary winding of the coupled inductor Tr , and the auxiliary inductor Laux connect in series to supply the power for the output load in the auxiliary circuit through the diode D2 .

At the same time, the input power source, the secondary winding of the coupled inductor Tr , the clamped capacitor C1 , and the middlevoltage capacitor (C2 ) connect in series to release the energy into the HVSC through the diode D4

6) Mode 6 (t5 –t6 ) [Fig. 4(f)]:

At time t=t5 , this mode begins when the main switch S1 is triggered. The auxiliary inductor current iL aux needs time to decay to zero, the diode D2 persistently conducts.

In this mode, the input power source, the clamped capacitor C1 , the secondary winding of the coupled inductor Tr , and the middle-voltage capacitor C2 still connect in series to release the energy into the HVSC through the diodeD4 .

SIMULATION MODEL

RESULTS

Input voltage

Input current

Output voltage

Output voltage

Output current

Output power

Iaux

ID2

Switching current

Switching voltage:

CONCLUSION: In order to extend the line range of the IBR

converter

while maintaining high weighted efficiency, a special

hybrid frequency modulation scheme is proposed.

The scheme reduces core and conduction loss

dramatically by decreasing the applied volt-seconds

at the transformer and improving the switching

period utilization.

At the nominal voltage, the CEC efficiency is improved by 4%.With the average of low,nominal, and high input voltage,

the CEC efficiency is improved by 1.5%. It should be noted that such a significant efficiency improvement was achieved with no other circuit changes.

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